1. Field of the Invention
The present invention relates to a wind type coil, and more particularly to a wind type coil which is used as an inductance element in a filter circuit, an oscillation circuit or the like.
2. Description of Related Art
Generally, a wire used for a wind type coil is a copper wire with an insulating coat such as polyurethane. Conventionally, just before and after the wire is wound around a body of a core, the insulating coat of the wire is removed at the winding start portion and the winding end portion, and the bare portions of the wire are soldered to electrodes formed on the core.
Soldering requires an after process of flux cleaning, and a cleaner used for the flux cleaning contains a substance which destroys the ozone layer. Thus, soldering is a problem from the viewpoint of environmental protection. Further, there are technological problems in soldering as follows: flux is likely to remain even after the flux cleaning, and the residual flux may damage the insulating coat of the wire; and since copper diffuses into solder easily, the copper wire partly diffuses into solder during the soldering process and becomes thin, which may cause breaking of the wire.